Mill



Patented Jan. 15, 1946 UNITED STATES PATENT oFFlcE MILL Reuben S. Tice, Monterey, Calif.`

ADDllCatlOn July 19, i543, Serial N0. 495,271

(Cl. 24l-55) 7 Claims.v

This invention relates to a, mill for breaking up relatively brittle material such as rock, ore, glass, etc.

The. mill of this invention is the type in which a. rotor is enclosed in a. polygonal sided housing, and which rotor includes hammers that revolve about the rotor axis when the rotor is rotated and that coact with the housing walls for shattering the material to be broken by repeated blows delivered thereto by the hammers and walls as the material is caused to move through the mill from an inlet-opening in its walls to a discharge opening. Such general type of mill is disclosed in my United States Letters Patent No. 2,152,108, of April`3, 1939.

Some of the objects of this invention are to provide a mill of the above general type so designed as to be simple, economical to malla-and in `which the parts that are subjected to abrasive Wear will last longer than heretofore and Will function Without loss of efficiency up to the time they require replacement, and which mill is also yadapted to be quickly adjusted for delivering broken material in different sizes as may be de' sired, from microscopic particles appreciably smaller than that Classifiable Iby screens to larger easily Classifiable particles.

Other objects and advantages will appear in the drawing and description.

In the mill of this invention it is pertinent to note that it functions mainly as an impact mill, breaking up material by sharply delivered blows, and it do'es not break up the greater mass of material by a grinding action, as in some mills that are provided rotor vanes and stationary grids, or ridges on the housing walls past which the varies' move with a very small clearance.

In the drawing,

Fig. 1 is a part sectional, part elevational view of a mill illustrating the invention, and the sectional portion of which is taken substantially along the line i--I of Fig. 2.

Fig. 2 is a sectional view of the mill as seen from line 2-2 of Fig. 1.

Fig. 3 is an elevational view of the front or feed side of the mill, and in this view a classifying system is diagrammatically indicated including a suction fan or suction blower. The millis shown in this system. v

Fig. 4 is a perspective view of one of the hammers.

Fig. 5 is an enlarged fragmentary sectional view taken through the housing wall along line 5-5 of Fig. 3.

Fig. 6 is an edge view of a hammer that may the walls I, 2. A housing or casting 4 that includes a base 5 may |be secured to the rear wall 2 for supporting the mill with its central axis' horizontal. The shaft 3 may be directly connected with a motor in said housing 4 for rotating shaft 3, or the said shaft may have a pulley secured thereto for a belt connection with a line v shaft pulley. The particular manner of driving shaft 3, and consequently the rotor that is adapted to be secured thereon between end walls I, 2, is immaterial, so long as a source of power may be connected with shaft 3 for rotating it at the desired speed or speeds.

\ The sides of the housing are preferably six in number, making the housing hexagonal sided. The sides are of the same sizeand each includes an outer wall and an inner wall or liner, the latter being preferably of hardened metal specially resistant to abrasive wear by rocks, ore,

glass, and the like'.

Five of the outer side walls of the housing commencing-with the top wall 8 and including the I next four walls 'l in succession counterclockwlse around the housing as seen in Fig. 1, are formed integrally, or are welded together, and may also be Welded .to the rear wall 2. The last or sixth side wall 8 which is adjacent the top wall 6, is preferably removafbly secured to the rear wall 2 by a plurality of spaced stud bolts, one of whichl is indicated at 9 in Fig. 2.

The liners or inner Walls I0 are separable from each'other and from the end walls of the housing, there being a. liner foreach outer side wall.

Bolts and nut connections Il removably secure each liner to each outer side wall adjacent thereto. y

The front end l of the housing is removably secured to the outside walls 6, l, 8 of the housing by bolts l2 (Fig. 3). Thus the side wall 8 and its liner may be removed from the housing without removal of the bolt and nut connections Il, and without removal of the front wall I from the housing, but upon removal of the front end wall circular opening that is coaxial with shaft 3 and with the circular opening in front end I (Fig. 2) and a frusta-conical member I3. having its larger diam-- eter end substantially coincident with the central opening in said disk I4 extends through the central opening in end I. Thus member I3 is coaxial with the central aligned openings in end I and in disk I4 and may be formed integrally with.

disk I4 or may be secured to the latter by any suitable means. A lfeed chute or conduit I1 from any source of supply of the material to be broken may extend into the smaller diameter end of member I6 for feeding such material I3 (Fig. 2) to between disks I3, I4 centrally thereof.

The cross members I5, in addition to holding disks I3, I4 rigidly together for rotation as a unit, may also support the hammers. These cross members I may be rectangular plates secured at two of their opposite edges to disks I3, I4 and they extend tangentially from a circular line substantially coincident with the central opening in disk I4 toward the outer edges oi' the disks I3, I4. The outer ends of plates or members I5 preferably terminate a short distance inwardly of the outer edges of said disks I3, I4 and the latter are preferably of substantially the same outside diameter with their peripheries relatively close to the liners III, but slightly spaced therefrom, as seen in Fig. 1.

Each of the hammers I9 may comprise a relatively thick plate of metal specially hardened to resist the abrasive wear of material I8, such as rocks, ore, glass, etc. Hammers I9 are of rectangular contour, each being formed with a flat side i zo (Fig. 4) that is adapted m ne nat on the outwardly facing side of each plate I5, and in which position the two opposite side edges of each hammer are respectively adjacent disks I3, I4 and the outer end edge 2| ot each hammer adjacent the peripheries of disks I3, I4 is of a contour (in the direction of the thickness of each hammer) that substantially corresponds with the curve of the said peripheries.

One convenient means for removably securing the hammers to the plates I5 respectively, is to form each plate I5 with a pair of spaced openings 22 disposed on a line intermediate the disks I3, I4, and to provide each hammer I9 with spaced projections 23 having right angle outer ends 24. The ends 24 extend toward the outer ends 2I of the hammers and openings 22 are adapted to pass the ends 24 therethrough, after which the hammer is slipped on plate I5 outwardly toward the outer edges of the disks and thus the ends 24 will extend over the edges of openings 22 to hold the hammer against the plates I 5.

sertedthrougheachsuchopeningindiskllsnd y,is threaded into each member 23.

as is indicated in Fig. 1. and then only when the mill is stopped, since centrifugal force will hold the hammer to the plates by means of the projections 23 and ends 24 when the hammers are being revolved.

A single method of removlngthe hammers is to provide an opening 23 in front end I adjacent the side 3 at a point scanned by the bolts 21 when the disks and hammers are revolved. This opening may be normally closed by a plug 23, but to remove any hammer the plug is removed and the disks turned until the desired bolt 21 is opposite the said opening. I'he side 3 and its liner being removed, the hammer adiacent such open side vmay be readily removed from its member Il and taken from the mill through tbe opening upon removal of bolt 21 through the opening in side I. A newV hammer can then be quickly installed through the same open side of the housing and plug 23 reinserted.

Formed in side wall 3 may be a discharge opening in which is secured a discharge conduit 30. Or an opening 3l (Fig. 3) may be formed in end wall I for a discharge conduit similar to conduit 3o. The opening 3I may be closed by a plate 32 (Fig. 3) when conduit 3o is used, or the opening for conduit 3l may be closed by such plate when opening 3I is used.

Since the opening 3l is in end I the disk I4 will generally extend over the opening so that the only material in the mill that reaches said opening is such material as passes over the edge of disk I4 to between said disk and end I.

A suction .fan or blower 33 (Fig. 3) may be connected with either conduit 33 or a conduit (not shown) communicating with 3l, as the case may be, for withdrawing such material from the housing as is suniciently small and light to be so withdrawn, although the action of the hammers themselves and their relation to the central opening in disk I4 functions as a blower for causing radial outward movement of broken particles of material in the housing.

Where a classiiication of materials is desired, I may insert one or more conventional cyclone classifiers 34 in the conduit leading to the fan or blower 33 (Fig.3),and material that is coarser than desired may be returned to the chute or conduit I1 for repassage through the mill.

The neness to which the material passing through the mill is reduced may be determined to a considerable degree by the closeness with which the outer ends of the hammers clear the positioned so that the hooked ends 24 hold them against plate I5. A headed bolt 21 is then inliners I0. The closer said ends are to the liners the finer will the material be broken, since the material will more frequently strike the hammers and liners with each revolution of the hammers. Also a finer material will be drawn from the mill through opening 3i than through conduit 30, and a screen 35 (Fig. 2) may be in the opening 3| for preventing undesirably large pieces from passing through said opening.

The speed at which ythe hammers revolve as disks I3, I4 are rotated may vary. In some in stances the disks may berotated at 1000 R. P. M. and at other times they may be rotated at say 3600 R. P. M., or at any other desired speed.

The hammer 38 shown in Fig. 6 is adapted to be secured to any plate Il. and this hammer is the same as hammers I9 except that it is thickened at 31 at its outer end. This type of hammer may be standard for all work, whether nne or coarser material is to be produced, but it is particularly adapted for use when there is small clearance between the ends of the hammers and the liners III so as to compensate for parasitic abrasive wear on the hammers at their outer ends.

With the hammers'arranged as shown in Fig. l .between disks I3, I4, the abrasive wear on the hammers is such as to ultimately produce a concavity on the exposed sides ofy the hammers, but which concavity does not reduce the eiiiciency of the mill for pulverizing material. This concavity is both transversely and longitudinally of the flat exposed side of each hammer and as it extends over snbstantially the full area. of such side the wear on the hammers is relatively slow.

There is practically no detrimental wear on disks I3, I4 or on the ends of the housing, and the 'liners I0 are long wearing and easily replaceable.

I'he hammers are revolved in the direction of the arrows 38 in Fig. 1, and while the housing Lfor the rotor is generally vertical as seen in Fig.

2, it need not necessarily be supported in this position since in some instances, a horizontal or slanted position is desirable. However, the substantially tangential arrangement of the hammers between disks and the substantially center inlet in the housing to the inner ends of the hammers are quite important, although I do not wish to be limited to this exact structure.

In the claims the use of the term "polygonal sided" in referring to the housing is to be understood as defining the inner surfaces of the inner walls III that face radially inwardly `toward the rotor. The outer walls 6, 1, 8 of the housing support the inner walls or liners II) and may also be arranged to meet the requirements for a polygonal sided housing but the actual arrangement of thesaid outer walls is more or less immaterial.

Th'e drawings and description are to be considered illustrative of the invention and not restrictive thereof.

Having described the invention, I claim:

1. A. mill of the character described comprising a polygonal-sided drum-like housing having parallel coaxial end walls one of which is formed with an inlet opening substantially centrally thereof for material to be broken; a pair of opposed disks respectively closely adjacent said end walls to preclude passage of relatively coarse particles of said material between each diskand the Wall adjacent thereto and rotatable about the central axis ofsaid end walls; an opening substantially `coaxial with said inlet opening formed in the disk adjacent said latter opening; a plurality of hammers between said disks equally spaced from eachother and from said axis; said opening in said disk being circular and said hammers extending substantially tangentially of the edges of said circular opening to substantially the outer edges of said disks; means for securing said hammersto said disks for revolving therewith about said axis; means for so revolving said disks; and an outlet opening formed in one of the walls of said housing spaced outwardly of said inlet opening for discharge of broken material from said housing, the sides of said housing being substantially equally spaced from said axis.

.2. A nill of the character described comprising a polygonal-sided drum-like housing having opposed end walls; a shaft rotatably extending through one of said end walls into said housing; a pair of spaced opposed disks within said housing secured tosaid shaft for rotation with the latter; a plurality of equally spaced hammers secured between said disks for rotation therewith about the axis of said shaft when the latter is rotated and means for so rotating said shaft in one direction; means for conducting material to the path of travel of said hammers during revolutionthereof about said axis for breaking by said hammers, and a discharge opening formed in one of the walls of said housing forl discharge of such material from said housing after breakage thereof by said hammers; said disks being circular and coaxial, and said hammers being rectangular plates positioned within the confines of the peripheries of said disks with one of their edges adjacent the peripheral. edges of the disks and extending inwardly from said latter edges generally toward the axis of said shaft, each of said plates being solldand of substantially uniform thickness for-about half its length commencing from its inner edge that is nearest said axis, and the` remainder being progressively thicker in direction toward its outer edge that is opposite said inner edge, the increased thickness of said remainder being on the leading side of each plate during its revolution in said direction and the opposite side of each plate being planar.

3*. A mill ofthe character described comprising a polygonal-sided drum-like housing having opposed end walls; a shaft rotatably extending through one of said end walls centrally thereof into saidhousing; a pair of spaced opposed disks within said housing secured to said shaft for rotation therewith; a plurality of equally spaced vrrembers rigidly connecting said disks each removably supporting a hammer element thereon;

a plurality of such hammer elements; means removably securing each such element to each of said members;` said hammer elements extending between said disks at right angles and generally radilally outwardly relative to the axis of said shaft; a conduit extending through one of said end walls into said housing for conducting material to be broken to said hammers; a discharge outlet formed in one of the walls of said housing for discharge of broken material from the housing; the said spaced members being plates extending between said disks respectively formed with openings intermediate the said disks; the means for securing said hammer elements to said plates comprising projections thereon extending through said openings and provided with hooked end portions integral therewith extending over the sides of said plates opposite the hammer elements respectively secured thereto; and means for revolving said shaft in a direction in which the said hammer elements are leading with respect to said plates the said openings in said plates being of sulcient width to permit passage of said hooked end portions therethrough when said projections are moved to one of the sides of said openings.

4. A mill of the character described comprising a polygonal-sided drum-like housing having opposed vertical end walls; a shaft rotatably extending through one of said end walls centrally thereof into said housing; a pair of spaced opposed disks within said housing4 secured to said shaft for rotation therewith; a plurality of equally spaced members rigidly connecting said disks each removably supporting a hammer element thereon; a plurality of such hammer elements;

each of said members; said hammer elements extending between said disks at right angles and generally radially outwardly relative to the axis -of said shaft; a horizontally. extending conduit extending through one of said end walls into said housing for conducting material to be broken to said hammers; a discharge outlet formed in one of the walls of said housing for discharge of broken material from the housing; sa-id conduit Ibeing generally of frusto-conical shape with its larger diameter end secured to one of said disks coaxial with the axis of said shaft; the end wall adjacent said last mentioned disk being formed with an opening, and said conduit rotatably extending through said opening; the said disk to which said conduit is secured being formed with an opening coaxial with the larger diameter end of said conduit and of substantially the same diameter as said latter end and means for feeding material directly into the lower side of said conduit at a point outwardly of the said end wall through which it extends whereby said conduit will function as a distributor for said material. A

5. A mill of the character describedcomprising a drum-like housing having opposed end walls 'connected by side walls,` said side .walls being provided with a, plurality of uniform sized radially inwardly facing planar striking surfaces in edge to edge relationship around the central axis of the housing and equally spaced from said axis, a pair of spaced opposed disks within said housing coaxial with the latter and respectively positioned relatively close to said end walls to prevent lodgement and passage of coarse material between said disks and said end walls, a shaft rotatably extending through one of said end walls coaxial therewith supporting/said disks for rotation with said shaft, a central circular opening formed in one of said disks and a frustoconical member secured atI its larger diameter end to said last mentioned disk at the edges of said opening and rotatably extending through the end wall of the housing that is adjacent thereto to outside said housing, an opening formed in said last mentioned housing coaxial with the opening in said disk for passing said member therethrough, an outlet in said housing in edge to edge relationship around the central axis of the housing and equally spaced from said axis, a pair of spaced opposed disks within said housing coaxial with the latter and respectively positioned relatively close kto said end walls to prevent lodgement and passage of coarse material between said disks and said end walls, a shaft rotatably extending through one of said end walls coaxial therewith supporting said disks for rotation with said shaft, a central circular opening formed in one of said disks and a frustoconlcal member secured at its larger diameter end to said last mentioned disk at the edges of said opening and rotatably extending through the end wall of the housing that is adjacent thereto to outside said housing, an opening formed in said last mentioned housing coaxial with the opening in said disk for passing said member therethrough, an outlet in said housing spaced radially outwardly of the opening in said disk, and a plurality of equally spaced hammers between said disks extending tangentially from the edges of the said opening in one of said disks to the peripheral edges of the disks, the outer edges of said. disks and the outer ends of said hammers being relatively close tosaid striking surfaces and equally spaced therefrom, and means for rotating said shaft for revolving said hammers about the axis of said shaft with their inner ends nearest said opening in said disk leading their outer ends.

7. A mill of the character described comprising a drum-like polygonal-sided housing having parallel opposed vertical end walls, a pair of opposed disks within said housing respectively positioned closely adjacent said end walls and parallel therewith, members connecting said disks, a horizontal shaft supporting said disks for rotation therewith, coaxial openings respec- 40 tively centrally in one of said disks and in the end wall adjacent thereto, a plurality of haml mers between said disks extending from the cention eachV hammer opposite said opening. and

an additional opening formed in one of the side walls of said housing for removal of the said hammers through said additional op'ening when said means is actuated for releasing said hammers from said members respectively, a closure for said last mentioned opening.

REUBEN S. TICE. 

